Role of the half-barrels subdomains on the stability of beta-glucosidases

• Grant number: 14/16913-8
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: May 01, 2015
• End date: November 30, 2018
• Field of knowledge: Biological Sciences - Biochemistry - Enzymology
• Agreement: Coordination of Improvement of Higher Education Personnel (CAPES)
• Principal Investigator: Sandro Roberto Marana
• Grantee: Maira Artischeff Frutuoso
• Host Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Protein domains are segments with stable and independent folding (Richardson, 1981; Dootlitle, 1995; Porter e Rose, 2012). Based on this definition, the structure of the (beta/alpha)8 barrels proteins was shown to be composed by two domains corresponding to its N- and C-terminal halves. In agreement, the analysis of the contact map of the beta-glucosidases GH1, also (beta/alpha)8 barrels, indicated the presence of two domains formed by sets of residues which mostly form intra-group interactions (Smith et al., 2013). These two domains are the N- and C-terminal halves of the beta-glucosidases GH1. Therefore, both approaches indicated that (beta/alpha)8 barrels proteins are formed by two domains corresponding to the N- and C-terminal halves. The objective of this project is to understand how the specific properties of the half-barrel domains are combined resulting in the properties of the (beta/alpha)8 barrels. The thermostable beta-glucosidase from Thermatoga maritima (Tmbglu), two beta-glucosidases from Paenebacillus polymyxa (bglA e bglB) and chimeric proteins formed by the combination of the N- e C-terminal halves of these enzymes (NTmbglu-CbglB, NbglB-CTmbglu, NbglA-CbglB e NbglB-CbglA) will be evaluated about their thermostability and stability in urea. Considering that the half-barrel domains should be thermodynamically stable units, it should be possible to detected their contributions to the chimera beta-glucosidases stability evaluating the changes in the rate constant for thermal denaturation and the transition temperature. In addition to that, the specific stability of each half-barrel domain in urea, evaluated by the "m" parameter, could be compared to the stability of the native and chimera beta-glucosidases, revealing how the specific stability of each domain combines to result in the stability of the entire (beta/alpha)8 barrel. (AU)

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

FRUTUOSO, Maira Artischeff. Contribution of (β/α)4 subdomains to the stability and activity of β-glycosidases GH1 with (β/α)8 barrel structure. 2019. Doctoral Thesis - Universidade de São Paulo (USP). Conjunto das Químicas (IQ e FCF) (CQ/DBDCQ) São Paulo.